Components:
Magnetos
Magnetos are highly reliable electrical generators. They are engine driven and independent of the aircraft's electrical system and independent of each other. What does this mean? It means that they will continue to run and supply electrical currents even if your electrical system shuts down. It also means that if one of your magnetos dies, the other is still capable of running on its own. As long as the engine continues to run, the magnetos will continue to produce electricity.
So how does it work and what does it doe? Think of a magneto as a magnet that spins constantly near a coil. As the magnet spins by the coil, it creates a periodic high-voltage. As the coils release their high voltage, the spark plugs ignite the fuel-air mixture in the cylinder.
Click here to see different parts of a magneto and how it is built: Breaking Down the Magneto
Figure 1
Spark Plugs
Spark Plugs provide the source of ignition. The average piston engine will have 4 cylinders. Each cylinder will have 2 spark plugs, each connected to a separate magneto. Figure 1 above shows how each magneto is connected to each cylinder. As magnetos create electricity, they send voltages to the spark plugs, which then ignite the fuel/air mixture inside of the cylinder. Why are their 2 spark plugs in each cylinder? Isn’t 1 enough? Let’s talk about that for a second. If you haven’t noticed in any of your training yet, aviation is all about having a backup plan. What happens if a spark plug failed? Thinks could go south pretty quick. Also, what if your magneto died? This would then cut off all 4 spark plugs and you’d have an engine failure. So lets go back to the dual spark plug with 2 magnetos. One of those magnetos dies, you have another one supplying electricity to one spark plug in each cylinder. Your plane can run on only one magneto; this gives you time to find a suitable airport and get some the problem resolved. You always want a backup system. The dual spark plug system helps create reliability and even combustion, as well as higher power outputs.
For a very simple explanation, check out this Video. Take note that in the video, the concept has been simplified by showing a cylinder with only one spark plug.
Ignition switch
The Ignition Switch is inside the aircraft and controls the magnetos. The switch has 5 positions, which are: OFF, R, L, BOTH, START. R and L stand for right and left, if that needed to be clarified. When in the R or L position, only the magneto associated with that position will be activated, because remember, we have 2 magnetos. Then BOTH position activates both magnetos.
The Starter
Combustion
Abnormal Combustion
Shut Down
Engine Systems Video: https://www.youtube.com/watch?v=W9ICNLsDP9E